Map diff util

mapdiff.kt

sealed class MapDiffResult<T : Any,V : Any>  {
    data class Added<T : Any,V : Any>(val key : T, val v : V) : MapDiffResult<T, V>()
    data class Removed<T : Any,V : Any>(val key : T, val oldValue : V) : MapDiffResult<T, V>()
    data class Changed<T : Any,V : Any>(val key : T, val new : V, val old :V) : MapDiffResult<T, V>()
}

fun <K : Any,V : Any> Map<K,V>.diffMaps(to: Map<K,V>, isSame : (V, V?) -> Boolean = { v,v2 -> v == v2 }) : List<MapDiffResult<K, V>> {

    val from = this
    val changes = mutableListOf<MapDiffResult<K, V>>()

    to.forEach { k, v ->
        if(!from.containsKey(k)) {
            changes.add(MapDiffResult.Added(k, v))
        } else {
            if(!isSame(v,from[k])) {
                changes.add(MapDiffResult.Changed(k, v, from[k]!!))
            }
        }
    }

    from.forEach { k, v ->
        if(!to.containsKey(k)) {
            changes.add(MapDiffResult.Removed(k, v))
        }
    }
    return changes
}